Antibody (Ab) Homologous Competition (Bmax & KD)

A homologous competition is a concentration response curve with an unlabeled compound that is identical to the radioligand being used. Radioligand concentration is constant in the experiment. Homologous competition experiments can be used as an alternative to saturation experiments to determine receptor affinity (Kd) and density (Bmax). When using [125I]-ligands, a non-radioactive iodo-ligand should be used if possible.